Chứng tỏ rằng A = 1/3 − 2/3^2 + 3/3^3 − 4/3^4 + … + 99/3^99 − 100/3^100 < 14
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Bài 5: Chứng tỏ rằng
\( A = \frac{1}{3} - \frac{2}{3^2} + \frac{3}{3^3} - \frac{4}{3^4} + \ldots + \frac{99}{3^{99}} - \frac{100}{3^{100}} < \frac{1}{4} \)
